|By: Diana Clarke|
If you’re looking for something fun and creative to do this summer, consider blueprinting, an alternative photographic process. But you won’t be creating an image for construction. Instead, you’ll learn how to use the sun to transform a design into a work of art on fabric. You may wish to design a scarf, t-shirt, or any other garment or fashion accessory. You can also make an art print to frame and display. Kids would also love to do this easy and fun activity.
The blueprinting process or cyanotype was invented in 1842 by an English astronomer, Sir John Herschel. But it wasn’t until the industrial revolution that the process was used widely to copy drawings by architects, builders, and engineers. A blueprint used to contain white lines on a blue background. Today the standard blueprint process contains blue lines on a white background.
Preparing to Make Blueprints
Blueprinting on fabric begins with the fabric being saturated with a solution of two chemicals--ammonium ferric citrate and potassium ferricyanide (water soluble iron salts), which react to UV light producing the compound Prussian blue. You’ll be working with treated fabric. Therefore, you won’t need to mix any chemicals. The treated fabric is safe to use. All you’ll need are gloves and perhap an apron or old clothes and a drop cloth to keep things from being stained.
It is best to use a natural fiber such as 100% cotton, rayon or silk. If you use a fabric of cotton and polyester blend, the background color will not be a rich indigo blue and may fade in time. Also, before you begin your project, wash the fabric to remove sizing and conditioners, which would interfere with the chemical reaction.
Blueprinting on a Clear Summer Day
The best time of day to print your fabric is around noon when the sun is overhead and the sky is clear. The UV light is most intense and the angle of the sun will help print a crisp picture. If the sun is low in the sky, you’ll need to prop up your treated fabric so that it will be perpendicular to the sun. In this way, shadows and a fuzzy picture can be avoided. Also, select a place that is wind-free; any movement will produce a fuzzy picture.
When you are ready to begin, place a large piece of plywood or foam board on a table and take the treated fabric out of the lightproof bag. You should be indoors away from the sunlight when you do this. Place the fabric on the support and add to the fabric the objects that will create a design. Try to do this quickly. Although you will have a few minutes, the treated fabric will start to change color slowly.
Some ideas for designs:
I use photo imaging software to change a scanned or digital photo to a negative. Next, I print the negative on a transparency sheet. After that, I place the sheet on the fabric and cover the transparency and fabric with non-UV coated acrylic.
Put a piece of glass or acrylic (non-UV coated) on top of the design. This will help maintain close contact between the design and the treated fabric. Consequently, movement will be prevented and light won’t be able to expose the covered area. You may also choose to pin the objects to the treated fabric. If the acrylic or glass is not at least as large as the fabric, lines will print.
Fixing the Blueprint
After 2-15 minutes (depending upon the time of day and year) when your fabric becomes dark green, bring the fabric inside and rinse it in a tub of water. Keep rinsing until the water is clear. The non-exposed chemicals will rinse out. With white fabric, you’ll see the print appear in white and blue. If you have fuchsia fabric, the print will be purple and fuchsia; yellow fabric will produce a green and yellow print; turquoise will produce a blue-green and turquoise print. The fabric color will appear in non-exposed areas after rinsing if the objects covering those areas are opaque. If the objects are transparent or transluscent, light will get through and expose that area of the print.
After thoroughly rinsing the fabric, hang it to dry inside.
Care of Your Printed Fabric
When you need to wash the fabric, always select a non- phosphate liquid soap such as Woolite or Dove. It is better to hand wash than machine wash. If you use a powder detergent with phosphate, your print will fade or contain yellow or brown blotches. If you leave your fabric to dry outside, it will fade over time. If you want to have it drycleaned, take a swatch to the cleaners for testing. With gentle care, your fabric will fabric will
Hewitt, Barbara. Blueprints on Fabric: Innovative Uses for Cyanotype. Loveland, Colorado: Interweave Press, 1995.